The present invention relates to a gearshift apparatus for an automobile with an automatic clutch such as an electromagnetic powder clutch.
An electromagnetic powder clutch for an automobile comprises an annular drive member secured to a crankshaft of an engine, a magnetizing coil provided in the drive member, a driven member secured to an input shaft of a transmission spaced from the drive member, magnetic powder provided in the space between the drive and driven members, and a shift lever for changing gears in the transmission. The shift lever is provided with a tiltable knob and switches. The knob is tilted with respect to the shift lever by a force applied through the driver's hand, when the shift lever is shifted. The switches are actuated by the knob for controlling the electric current flowing through the magnetizing coil. As an accelerator pedal is depressed, the clutch current passing through the coil increases. The magnetic powder is aggregated in the gap between the drive member and the driven member, so that the driven member is coupled to the drive member. Thus, the automobile can be smoothly started by suitably depressing the accelerator pedal by slipping of both members of the clutch. Such system is disclosed in a plurality of patent publications, for example, in Japanese patent laid-open specification No. 56-60733.
Today, many cars are equipped with four-speed transmissions. Accordingly, the shift lever must be shifted along an H-shaped shift pattern for forward driving. Although no clutch pedal operation is required for driving the automobile provided with an electromagnetic powder clutch, the driver is not yet free from complex shift lever operation. On the other hand, since the electromagnetic powder clutch can be designed to have a long period of partial engagement by controlling the clutch current, the automobile can be started by a second speed gear of the transmission with such a long partial engagement. Therefore, it is possible to drive the automobile only by the second speed and fourth speed gears. Accordingly, the present invention has proposed to divide four forward-gear sets trains of the transmission into two groups, that is a high power transmission system comprising first speed and third speed gears and a low power transmission system comprising second speed and fourth speed gears. On an ordinary road, the automobile can be driven by the low power transmission system, and when high power is required as uphill driving, the high power transmission system is used.